Method and circuit for equalizing and compensating IQ imbalance simultaneously

Abstract

The present invention provides a method and circuit for equalizing and compensating IQ imbalance at the same time. The method includes: down-converting an RF signal to generate a baseband signal, and driving an adaptive equalizer to process the baseband signal for achieving equalization and IQ imbalance compensation simultaneously.

1. A method for equalizing a signal, comprising:
 down-converting an RF signal to generate a baseband signal; and 
 utilizing an adaptive equalizer to process the baseband signal such that the baseband signal is equalized and an IQ imbalance of the baseband signal is compensated simultaneously; 
 generating a plurality of equalization coefficients to process the baseband signal, wherein each equalization coefficient is a 2×2 matrix, and two elements on two respective diagonals of the 2×2 matrix are not equal; 
 wherein the adaptive equalizer processes the baseband signal under a time domain. 
 
   
   
     2. The method of  claim 1 , wherein the adaptive equalizer is one of a feed-forward equalizer (FFE) and a decision feedback equalizer (DFE). 
   
   
     3. The method of  claim 1 , wherein the RF signal is a digital TV signal. 
   
   
     4. The method of  claim 1 , wherein the adaptive equalizer executes a least-mean-square (LMS) algorithm. 
   
   
     5. The method of  claim 1 , wherein the adaptive equalizer comprises a plurality of equalization coefficients for compensating channel response and IQ imbalance. 
   
   
     6. A circuit for equalizing and compensating IQ imbalance simultaneously, comprising:
 a down converter for down-converting an RF signal to generate a baseband signal; and 
 an adaptive equalizer coupled to the down converter for receiving the baseband signal and processing the baseband signal such that the baseband signal is equalized and an IQ imbalance of the baseband signal is compensated simultaneously; 
 wherein the adaptive equalizer processes the baseband signal according to a plurality of equalization coefficients, wherein each equalization coefficient is a 2×2 matrix, and two elements on two respective diagonals of the 2×2 matrix are not equal; and 
 wherein the adaptive equalizer processes the baseband signal under a time domain. 
 
   
   
     7. The circuit of  claim 6 , wherein the adaptive equalizer is a feed-forward linear equalizer (FFE) or a decision feedback equalizer (DFE). 
   
   
     8. The circuit of  claim 6 , wherein the RF signal is a digital TV signal. 
   
   
     9. The circuit of  claim 6 , wherein the adaptive equalizer executes a least-mean-square (LMS) algorithm. 
   
   
     10. The circuit of  claim 6 , wherein the adaptive equalizer comprises a plurality of equalization coefficients, the equalization coefficients correspond to channel response and IQ imbalance. 
   
   
     11. A method for equalizing a signal, comprising:
 down-converting an RF signal to generate a baseband signal; 
 generating a plurality of equalization coefficients, wherein the equalization coefficients correspond to channel response and IQ imbalance; and 
 processing the baseband signal according to the equalization coefficients to equalize the baseband signal and compensate an IQ imbalance of the baseband signal; 
 wherein each equalization coefficient is a 2×2 matrix, and two elements on two respective diagonals of the 2×2 matrix are not equal; and 
 wherein the step of processing the baseband signal is performed under a time domain. 
 
   
   
     12. The method of  claim 11 , wherein the down-converting step is a direct down converting step. 
   
   
     13. The method of  claim 11 , wherein the RF signal is a digital TV signal. 
   
   
     14. The method of  claim 11 , wherein the down-converting step further comprises:
 filtering out a noise of the baseband signal. 
 
   
   
     15. The method of  claim 11 , further comprising:
 executing an adaptive algorithm to generate the equalization coefficients. 
 
   
   
     16. The method of  claim 15 , wherein the adaptive algorithm is a least-mean-square (LMS) algorithm.